Humerus head prosthesis

ABSTRACT

A humerus head prosthesis including a head and a shaft. A hollow quiver which has one or more openings in the jacket is arranged at the shaft proximally and below the head. The quiver is located at the level of the anatomical position of the tubercles and laterally at the shaft. The jacket openings are formed as threaded bores for screws.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a humerus head prosthesis.

2. Description of the Prior Art

A humerus head prosthesis or shoulder prosthesis of this kind is knownfrom the prior art. It has a head and a shaft. The head, whichcorresponds substantially to a spherical segment, can be releasablyconnected to the shaft via a neck. It has an eccentric bore for theneck. In humerus head prostheses there is the problem of the boneintegration of the tubercles at the prosthesis. The previously knownhumerus head prosthesis offers no practicable and reliable help forthis.

SUMMARY OF THE INVENTION

The object of the present invention is therefore to provide a humerushead prosthesis with an improved integration possibility of thetubercles.

The present invention provides a humerus head prosthesis that includes ahollow quiver arranged at the shaft and facilitates the integration ofthe tubercles at the prosthesis. It can be filled with bone shavings orbone splinters, with an ossification and a connection to or of thetubercles through the jacket openings being possible. In many cases of ashoulder lesion the tendon is still grown on at the tubercles, with thedetachment having taken place in the bone. The tendons with thetubercles can then again be secured to the humerus head prosthesis andintegrated via the ossification.

The jacket openings of the quiver also afford a possibility for theexact positioning and temporary securing of the tubercles at theanatomically correct location. For this purpose it is also provided inaccordance with the invention that the quiver is arranged subcapitallyat the level of the anatomical location of the tubercles and laterallyat the shaft. The proximally lying filling-in opening facilitates theintroduction of the bone shavings. The funnel-like quiver shape alsofacilitates this, with the funnel shape additionally assisting theanatomically correct positioning of the tubercles and in additionoffering more bone matter in the proximal region for the growing on thanin the distal region in an anatomically favorable manner.

In a particularly advantageous manner at least a portion of the jacketopenings is provided with screw threads, which permit an exactpositioning of the tubercles by means of bone screws. For improving thethrift it is advantageous in this to provide the threaded bore with ametric thread in order to be able to use economical standard screws withcompression collars.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a humerus head prosthesis in a bottom view as seen from thedistal end, and

FIG. 2 is a side view of the prosthesis of FIG. 1.

DETAILED DESCRIPTION OF SPECIFIC EXEMPLARY EMBODIMENTS

The humerus head prosthesis (1) consists of a substantiallyhemispherical head (2) and a shaft (3), which are connected via a neck(5). The connection between the neck (5) and the head (2) can bereleasable. The humerus head prosthesis (1) can have any desiredsuitable shape in the shaft and head region.

A hollow quiver (6) is arranged laterally at the prosthesis shaft (3)for the reception of bone shavings, bone splinters or the like. Thequiver (6) is located subcapitally at the level of the anatomicallocation of the tubercles and preferably terminates at the proximal endflush with the prosthesis shaft (3). In the quiver region the prosthesisshaft (3) can have a flattening or a cut-out. This facilitates on theone hand the attaching of the quiver (6) and increases the quiver volumeon the other hand.

The humerus head prosthesis (1) and the quiver (6) consist of a bodycompatible inert material, e.g. titanium. The quiver (6) has a vaultedshape and is connected with its edges to the shaft (3) in a suitableway, e.g. through welding or the like. In this, guides, centerings andother positioning and securing aids can be present.

The hollow quiver (6) has a funnel shape which widens proximally and hasa filling-in opening (10) proximally. Through this the bone shavings canbe filled in from the proximal direction. The head (2) can be removedfrom the neck (5) for this. A filling in beneath the placed on head isalso possible where appropriate.

The quiver has a jacket with one or more openings (8). The latter can becircular and have any other shape desired and can be punched free out ofthe jacket or be manufactured in another suitable manner. The quiverjacket can furthermore have one or more threaded bores (9). In this aportion of or all the openings (8) can be formed as threaded bores (9).The threaded bores (9) are preferably located in the lateral jacketarea.

The threaded bores have a metrical thread and can receive standardscrews (11). Otherwise, however, different kinds of screws with otherthreads can also be used. It is also possible to use screws withself-cutting threads or sheet metal lamina threads for connecting withsimple openings (8).

In the preferred embodiment the screws (11) also have a compressioncollar (12). The pot-like compression collar (12) has tips which projectat the edge side, which distribute the pressing force better and whichensure a secure screw holding.

The humerus head prosthesis (1) in accordance with the invention enablesthe exact integration of detached tubercles (non-illustrated). For this,one or more screws (11) are inserted via suitable passage bores into thetubercles and are fixed at the openings (8) or threaded bores (9) of thequiver (6) respectively.

The humerus head prosthesis (1) can otherwise have any further designfeatures desired. The shaft (3) has e.g. one or more longitudinallyextending ribs (4) for fixing in the humerus. The head (2) can have aneccentric reception opening for the neck (5). In addition it can haveturned out hollowings and other cut-outs to save material.

Modifications of the illustrated embodiment are possible in variousways. Thus the hollow quiver can have any other desired shape andposition at the prosthesis shaft (3). In addition the tubercles can besecured at the quiver (6) in a suitable manner other than by screws. Theopenings (8) or threaded bores (9) respectively can be uniformly ornon-uniformly distributed at the quiver jacket in the form shown. Theirnumber and arrangement can vary in any desired manner.

What is claimed is:
 1. A humerus head prosthesis comprising a head, ashaft and a holder for filling-in bone splinters, wherein the holder isarranged subcapitally at the level of an anatomic location of tuberclesand laterally at the shaft and terminates at a proximal end flush withthe shaft, and wherein the holder has a filling-in opening proximallyand at least one additional opening, wherein the prosthesis comprises atleast one bone screw that fits into at least part of at least oneadditional opening of the holder for fixing the tubercles to the holder.2. A humerus head prosthesis in accordance with claim 1, wherein theholder has a funnel shape that widens proximally.
 3. A humerus headprosthesis in accordance with claim 1, wherein the holder has at leastone threaded bore.
 4. A humerus head prosthesis in accordance claim 3,wherein the at least one threaded bore has a metrical thread forreception of standard screws with compression collars.